Blow for Ainslie at America's Cup yacht race as Kiwis take lead

Land Rover BAR skipper Ben Ainslie, pictured in May 2017, faced a setback when his team's boat suffered severe damage, preventing them from racing

Ben Ainslie's America's Cup hopes suffered a devastating bodyblow on Monday after his badly damaged Land Rover BAR boat retired from its opening scrap with Emirates Team New Zealand before conceding race two.

A dramatic start to the day's racing on Bermuda's Great Sound began with Ainslie's team aiming to exploit powerful winds against the Kiwis in the opening race of their best-of-nine semi-final series.

But the British boat's challenge came unstuck shortly after the gate two turn, when they pulled up with what appeared to be a damaged camber arm.

The race was black flagged soon afterwards, handing Team New Zealand a vital early win in their quest to reach the America's Cup final.

It got worse for Ainslie's crew soon after they returned to base, with confirmation that the damage to the boat was so serious that they would be unable to patch the craft up for their second race of the day against the New Zealanders.

The British challenge now has a mountain to climb to remain alive with the Kiwis leading 2-0 in the series and needing only three more wins to advance.

Ainslie later said the crew had heard a loud crunching sound after the second turn which prompted the decision to stop.

"It was a pretty loud bang. We knew something fundamental was wrong," he said. "It's a good job we stopped when we did because we'd probably have bits of the wing hanging around our ears otherwise.

"It's a tough one for the team. But it's a technical sport. Sometimes you get failures like this -- you have to take it on the chin."

Land Rover BAR now face a frantic 24 hours attempting to get their catamaran ready for Tuesday's third and fourth races in the series.

In the other semi-final on Monday, SoftBank Team Japan grabbed first blood in their duel with Sweden's Artemis Racing.

SoftBank's helmsman Dean Barker was pleased at a victory secured in challenging conditions.

"We're up against a very strong team and they've proven they've been pretty strong in these conditions," Barker said.

"For us to come out and put up a solid race was satisfying. The guys did a fantastic job around the course."